Cyanine dyestuffs



Patented Oct. 24, 1950 John David Kendall, Henry Walter Wood, and

John Raymond Majer, Ilford, England, assignors to Ilford Limited, Ilford, England, a

British company No Drawing. Application October 8, 1942, Serial No. 461,324. In Great Britain November 6,1941

' N J10 Claims.

This invention relates to dyestuffs and particularly to the production of dyestuffs capable of sensitising gelatino silver halide photographic emulsions.

)In our co-pending application Serial No. 461,3 2 filed on even date herewith now Patent 2,372,960 April 3, 1945, there is described the production of new dyestufi' intermediates by the reaction of a compound of the general Formula I:

1 C R4 (I) COR;

(where D is the residue of a heterocyclic nitrogen nucleus, R1 is an alkyl, hydroxy alkyl or aralkyl group, R2 is a hydrogen atom or an alkyl or aralkylgroup, R3 and R4 are hydrocarbon groups, e. g. alkyl, aryl or aralkyl groups, n is nought or 1 and m is 1, 3 or 5) with an alkylor aralkylmercaptan in the presence of a strong acid or an alkyl salt of a strong acid. Preferably, in this process the reaction conditions are kept as dry as possible, so that a very convenient acid is dry hydrochloric acid gas.

The general formula of the new intermediates is believed to be:

" -n--- Ri SR5 I I=(CH'-CH) b gl=(CH)m-CH=C B1 A g R3 11) (R5 is an alkylor aralkyl group, A is an acid radicle and the other symbols have the meaning assigned to them above).

The groups R1, R2, R3, R4 and R5 may variously be hydrogen atoms, alkyl groups, aryl groups and aralkyl groups as above defined. R1 is preferably a lower alkyl group, i. e. a methyl, ethyl, propyl or butyl group or, if an aralkyl group, is preferably a benzyl group. The group R2 may be a hydrogen atom but if not, is preferablya lower alkyl group as defined above. It may, however, be a higher alkyl group or an aralkyl group such as benzyl. Re and R4 again are preferably lower alkyl groups though they may be higher alkyl groups or aralkyl groups as in-theease of the group R2, or they may be arylgroupsfj The-'groupm is preferably a lower alkyl-group'though-it maybe a higher alkyl group or an aralkyl group as in the case of the group "R2; Any of the aforesaid alkyl, aryl or aralkyl groups may themselves contain"substituent groups, e. g. hydroxy or amino groups.

According to the present invention, dyestuffs are obtained by' reacting a dyestufi intermediate of'general Formula II (obtainable by the general process defined in our co-pending application Serial No. 461,322) with a cyclic compound containing a reactive methylene CH2) group. Examples of such compounds are as follows:

zoo-240.4)

(a) a five-membered ring compound containing the system:

where D is the residue of a heterocyclic nitrogenketo-methylene. ring and R is a hydrogen atom or a hydrocarbon group.

(b) a quaternary salt of a heterocyclic nitrogen compound having a reactive methyl group, monosubs'tituted methyl group or external methylene group in the a or position to a heterocyclic nitrogen atom;

(c) Carbocyclic compounds containing a ketcmethylene group.

The foregoing compoundsa, b and c are characterised by the fact that they all contain a reactive CH2 group either as an external substituent or in a ring system where it is activated by an adjacent keto group. (A reactive methyl group. which may be written as CII2-?H, includes a reactive methylene group.)

According to a further feature of the invention, when the five membered ring compound of type. a containing the system which is condensed with the said dyestufi intermediate, corresponds to the general formula:

membered ring compound containing the system:

which also corresponds to the general formula:

(R being a hydrogen atom or a hydrocarbon group and X being an oxygen atom or a sulphur atom), the product will once more contain a thione grouping, and by proceeding in this way the condensation may be repeated as often as desired; the final product obtained by any such series of condensations may be further condensed according to the invention with any of the other types of compound I) or above to give a dyestufi comprising two nuclear groups, for example, heterocyclic nitrogen nuclei, linked by a chain of any desired number of keto-thiazoline or ketooxazoline rings, which chain may also include other rings according to the condensations carried out.

Examples of compounds of type a which may be condensed with the said dyestufi" intermediate according to this invention are rhodanic acid (2-thio-4-keto-tetrahydrothiazole), oxarhodanic acid (2-thio-4-keto-tetrahydrooxazole), and the N-hydrocarbon derivatives of such compounds and the compounds enumerated in the specification of British Patent No. 426,718, filed October 3, 1933, namely oxindoles, 'pyrazole-5-ones, hydantgin, thio-hydantoin, \p-hydantoin and ,b-thioydant n- Compounds of type b which may be employed maybea'uy'of those which have been used or proposed for use in'the' many processes for'the production of cyanine and similar dyestuffs, for example, thiazoles, oxazoles, selenazoles and their polycyclic homologues such as those of the benzene; naphthalene, acenaphthene and anthracene series; pyridine and its polycyclic homologues such as quinoline and a and ,B naphthaquinolineslepidines; indolenines; diazines; such as pyrimidines and quin'azolines; diazoles (e. g. thio-BB-diazole);' oxazol nes, thiazolines and selenazolines. The polycyclic compounds of these series may also be substituted in the'carbocyclic rings with one or more grqups such as alkyl, aryl, amino, hydroxy, alkoxy" and methylene-dioxy groups, or by halogen atoms.

Examples of compounds of type c which may be employed are 1.3-indane-dione and the hyrin ne Where heterocyclic nitrogen nuclei are referred to in this specification they may be any of those which have been used or'proposed for use in the many processes for the production of cyanine and similar dyestuffs, for example, those listed above in connection with compounds of type b.

The formation of the dyestuffs is readily effected by heating the reagents together in the presence of a solvent and a base, e. g. pyridine,

piperidine, diethylamine, triethylamine and triethanolamine, or an inorganic base such as a solution of sodium or sodium acetate in ethyl alcohol.

Where reaction is effected with a quaternary salt of type b above, the quaternary salt may be formed in situ by heating together with the compounds of general formula II the corresponding heterocyclic base and suflicientof an alkyl or aralkyl ester, e. g. an alkyl'or aralkyl-p-toluene sulphonate, to convert said base to the quaternary salt.

Where the dyestuif is obtained in the form of a sulphate or an alkyl-p-toluene sulphonate, it may be converted to a salt of another acid by treatment with a solution of an alkali salt of such other acid, e. g. potassium chloride, po-

4 h ow n examples illustrate the invention: a

Example1 I Preparation of the dyestuffof the probable formula? 1.5 gms. of 1-(w-methyl-w-ethylthio-butadienyl) benzthiazole methochloride, i. e. the dyestufi intermediate obtained according to Example 1 of our co-pending application Serial No. 461,322 filed on even date herewith, and '1.45"gms. of l-methyl-f benzthiazole methiodide were dissolved in'20 cos. of ethyl alcohol and boiled. 1 gm. of sodiuin acetate was added and the mixture boiled for 20 minutes. on cooling, the d'yestuif separated as bright grass-green crystals. These were separated by filtration and recrystallised from methyl alcohol solution, the final product being obtained as bright green crystals melting at 234 C. This dyestuif when incorporated in a. gelatino silver iodobromide emulsion extends the sensitivity to about 8800A with a broad maximum at about 70095 to 76005.

Example 2 Preparation of the dyestuif of the probable formula:

The procedure of Example 1 was followed using 2.0 gms. of l-methyl-benzselenazole' ethi'odide instead of l-methyl-benzthiazole methiodide. The product was obtained as light blue flakes melting at 205" C. This dyestufi when incorporated in a gelatino silver iodobromide emulsion imparts a band of sensitivity extending from about 6000A a 8005. wi h a m x m at we A 7 Example 3 Breparation of the dyestuff of the probable e mi e 1 3.0 gms. of 2-(w-me thyl- -ethylth1o-butadienyl-) 1.3.3-trimethyl indolenine chloride, i. e. the dyestufi intermediate obtained according to Example 2 of our co-pending application Serial No. 461,322 filed on even date herewith, was dissolved in 25 cos. of ethyl alcohol and 4 gms. of finely divided l-methyl-benzthiazole methiodide was added. 2 cos. of triethylamine were then added and the solution shaken. Reaction set in immediately and after gently refluxing for 20 minutes, the liquid was allowed to cool. The desired dyestufi separated out and was removed by filtration. On recrystallisation from methyl alcohol solution the dyestuif was obtainedas lustrous green crystals i erate melting at 228 C. This dyestufi when incorporated in. a gelatin silver iodobromide emulsion imparts a band of sensitivity extendingi from about 60005 to about 8400A with maximaat about 7200A and about 7700A.

Example 4 Preparation of the dyestufi of the probable formulaz CHI CH: 1 OH of =oHon=on-o= o -o\ I 41H" CzH I 2 .5 gms. or 2-(w-methyl-'w-ethylthio-butadieh yl)-l.3. 3-trimethyl indolenine chloride and l; gms. of l-methyl-benzselenazole ethiodide were dissolved in cos. of ethyl alcohol. 2.5 cos. or triethylamine were added and the solution warmedfor'half an hour. The solution was then diluted with aqueous potassium iodidesolution whereupon the desired dyestuff separated as green crystals. On recrystallisation. from methyl" alcohol solution the dyestu'fi' was oh This dyestuff when incorporated in a gelatino silver iodobromide emulsion imparts a band of ver iodobromide emulsion imparts a band of sensitivity extending to about 7800A with maximum at about 7300A.

Example 5 Preparation of the dyestufi of the probable,

1 gm. of 1-methyl-5'.6-naphthathiazoleethiodide and 0.6 gm. of 2-(w methyl w-ethylthio-buta-' dienyl)-1.3. 3-trimethyl indolenine chloride were dissolved in cos. of dry ethyl alcohol and 1 cc.

- or'tnemyiamme was "added; The mixture was heated for 20 minutes during which a blue colour N C2H{..\I'

4 gins. of p-toluqui naldine ethio dide'and girls. of 2-(w-methyl-w-ethylthio-butadienyl) 4,3,3-

trimethyl indolenine chloride were dissolved in 25 cos. of dry ethyl alcohol and 500s. of triethylamine were added. The mixture was heated for 25 minutes whereupon a blue colour developed.

sensitivity extending from 5600A to 7800Awith ashanow maximumat about voooAa'zzooA.

Example 7 i Preparation of the dyestuif ,of iprobable formula: v,

1.5 gms. of 2-(w-methyl-w-ethylthio-butadienyl)-6-methy1"quinolin'e methochloride, i. e., the dyestufi intermediate obtained according-*to Ec'cample 3"of our co-pending application Serial No. 461,322 filed on even date herewith, and 1.5 gms. l-methylbenzthiazole ethiodide were dissolved 1111x25 cos. ;of ethyl alcohol and 1 gm; of sodium acetate was added. The solution was boiled for about 40 minutes whereuponthe desired dyestufl.

separated from solution. :It, was removed by fil-.

tration, Washed and dried. .It consisted of bright green, crystals 7 which after recrystallisation melted at 23030. This dyestufi, when incorporated in a gelatino silver iodobromide emulsion imparts a band of. sensitivity which extends. to 8000A with a maximum at-vsooA.

. I Emmet;

uPreparation of' the dyestuif "or the probable; formula:

2.1 gms. of 2-(w-methyl-w-ethylthio-butadienyl) 1.3.3-trimethyl indolenine iodide i. e. the intermediate prepared according to Example 4 of our eo-pending application Serial No. 461,322 filed on. eve n date herewith, and 2.3 gms. of lmethyl benzthiazole ethiodidewere dissolved in 25 -c cs; spirit and the mixture boiled. 1 gm. of fused sodium acetate was'then added and the mixture heated for 25 minutes. On cooling, atarry product separated and this was dissolved in acetone and treated'with ether when the dyestufi' precipitated out. .On recrystallisation from methyl alcohol it was obtained as shining green crystals melting at 220 C. This dyestuff when incorporated in a gelatino silver iodobromide emulsion imparts a band of sensitivity With a maximum at 7000A m the dyestufi oi the proba le fireparation of. formula:

C CH: ee ri eee eees The preparation was effected as in Example 8 using 1 gm. of N-m'ethyl rhodanic acid instead of the l-methyl ben'zthiazoleethiodide. The product was obtained as adarlf'fiurple solid melting at 235 'C. This dystufi'when incorporated in a gelatino silver iodobromide emulsion imparts a band of sensitivity extending to 73005 with a maximum at 6900A.

E am e Preparation of the dyestufi of the probable formula:

1.8 girls of 1(w-methyl-w-ethylthio-butadienyl) benz'thi'azole ethochlbridaiwhichmay be prepared as in Example 1 of our co-pending" application Serial No. 461,322 filed on even date herewith)" were 'mixed "with girls. of l-methylbenzthiazole ethiodide and dissolved in ccs'fof ethylalcohol. The soliition'wasbo'iled, 1.2 cos. of triethylamine. was addedind the "solution then boiled for minutes. "Theidyestuff crystallised out from solution and after. recrystallisation from methyl alcohol solution was obtained as shining grass-green crystals melting at 229 C. This dyestufiwhen incorporated in a gelatino silver iodobromide emulsion imparts a band of sensitivity extending to 79005.

Example 11 Preparation of the dyestufi of the probable formula: i I

1 -.8 g ns. of l(w -methyl-w-ethylthio-butadienyll benzselenazole methochloride (which may besiepared as in Example 5 of our"co-pehdingapplication Serial No. 461,322 filed on 'evfidate here with) and 1.5 'gms. of I-ni'ethyl-beh'zthiaz'oltz ethio'didewere reacted as in Example' 10.""The dye was obtained i'n'the form of light green crystals melting at 224 C. This dyestufi' when incorporated in a gelatino silver iodobromide emulsion impart's a band of sensitivity extending to QOOOA'with a maximum 9.1573005} Eeemelw Breparation of the, dyestuff of the pro able: formulas, i on, ci|"' CHaCHLOH Example 1 3 P epar t on o e d stuf cf. ee xq mula:

This dye was prepared by a process similarto that of Example 12 using 3.06 gms. of l-(w-m'ethyl wethylthio-butadienyl) benzthiazole-fi-hydroxyethyl chloride (which may be prepared by the process of Example 6 of our co-pending application Serial No. 461,322 filed on even date herewith), 3.21 gms. of l-methyl-benzthiazole-B- hydroxy-ethiodide, 20 ccs. of ethyl alcohol and 2 ccs. of' triethylamine. The dye was obtained-as green crystals melting at 226 C. This 'dyestufi when incorporated in a gelatino silver iodobromide emulsion imparts a'band of sensitivity ex tending to 8409A with'a maximum t 720%.

Example 14 This dye was prepared byte. method similar to that described in Example 12;.11Siljlg 4,2 gm s, 0L2- (w-ethyl-o-ethylthio butadienyl) 1.3.3 'trirnethyl indolenine iodide (which may be prepared as described inElxample '7 of our co-pending application Serial No. 461,322 filed on even date rewith), 3.6 gms. of l-methyl-benzselenazole e hiodide, 20 ccs. of ethyl alcohol and 1 cc. of triethylamine. The dye was obtained as grass-green needles melting at 192 C. This dyestuff when incorporated in a gelatino silver iodobromide emulsion imparts a band of sensitivity extending o 8 5 th a m im m 10 5 Preparation of the dyestufi of the probablefore 9 Example CHI CH Ha CH2 I emulsion imparts a band of sensivity extending to 3300A with a maximum at 7200A.

' V Example 16 Preparation of the dyestufi of the probable 0.4gm. of the dyestuif prepared according to Example 9 was mixed with 0.35 gm. of l-methylbenzthiazole and 3.0 gms. of methyl-p-toluene sulphonate. The mixture was fused for three hours at 140 C. 20 ccs. of pyridine were addedto the mixture and the mixture boiled for half an hour. The mixture was then poured into aqueous potassium iodide solution whereupon the dyestufi" crystallised out; On recrystallisation from methyl alcohol solution it was obtained as bronze crystals melting at 273 0.

Example 17 Preparation of the dyestufi' of the probable formula; Y

CH: on;

V o do S (l o=cH--oH=cH-d=c II/ v s 21 gms. of LS-indane-dione and 6.0 gms. of 2- (w methyl w-ethylthio-butadienyl) 1.3.3 tri methyl indolenine' iodide were dissolved in 20 ccs. of ethyl alcohol and boiled. 2.5 cos. of triethylamine were added and the mixture boiled for a further quarter of an hour. The mixture was then poured into water whereupon the prod- 'uct separated. After extraction with ethyl acetate the dyestuff was obtained as a purple solid melting at 163 C.

" Whilst in the foregoing examples the sensitising data is given in respect'of silver iodobromide emulsions-the dyes of this invention may be usefully employed in other types of photographic emulsion, e. g. silver chloride, silver bromide and silver chlorobromide emulsions.

What We claim is:

1. Process for the production of dyestuffs which comprises condensin by heating together a dyestufl intermediate of the general formula:

where D is the residue of a heterocyclic nitrogen nucleus of the type used in cyanine dyes, R1 is selected from theclass consisting of alkyl, hydroxy alkyl and aralkyl groups, R2 is selected from the class consisting of the hydrogen atom and alkyl andaralkylgroups, R3 is a hydrocarbon 'group, R5 is selected from the-class consist-1 ing of alkyl and. aralkyl groups, A is an'acid residue, andni's selected from thefclass consisting 'of'nought and 1, Withan alkyl'quaternary salt of aheterocyclic nitrogen compound of the type used in cyanine dyes containing a lower a1- kyl group in one of the a and 7 positions to the quaternary heterocyclic nitrogen atom.

2. Process for the production of dyestuffs which comprises condensing by heating together a dyestuff intermediate of the general formula;

B1 \A. Rl where D is the residue of a heterocyclic nitrogen nucleus of the type used in cyanine dyes, R1 is selected from the "class consisting of alkyl, hydroxy alkyl and aralkyl groups, R2 is selected from'the class consisting of the hydrogen atom and alk'yl and aralkyl groups, R3 is a hydrocarbon group, R5 is selected from the class consisting of alkyl and aralkyl groups, A is an acid residue, and n is selected from the class consisting of nought and 1, with a heterocyclic nitrogen keto-methylen'e' compound of the general formula:

where D is the residue of a heterocyclic nitrogen keto-methylenenucleus, and R is selected from the class consisting of the hydrogen atom and hydrocarbon groups.

3. Process'for the production of dyestuifs which comprises condensing by heating together a dyestuif intermediate of the general formula:

.--,---D-----| R2 SR5 N=(CH-CH),.=C =0H-0H=0 R1 \A R:

where D is the residue of a heterocyclic nitrogen nucleus vof the type usedin cyanine dyes, R1 is selected from the class consisting of alkyl, hydroxy alkyl and aralkyl groups, R2 is selected from the class consisting of the hydrogen atom and alkyl and aralkyl groups, R3 is a hydrocarbon group, R5 is selected from the classconsist- I ing of alkyl and aralkyl groups, A is an acid residue, and n is selected from the class consistin of nought and l, with a compound of the general formula:

H2C-X o=s O=GIII/ where X is selected from the group consisting of oxygen and sulphur and R is selected from the grou consisting of the hydrogen atom and hydrocarbon groups.

4. Process for the production of dyestuffs which comprises condensing by heating together a dyestuff intermediate of the general formula:

where D is the residue of a heterocyclic nitrogen nucleus of the type used in cyanine dyes, R1 is selected from the class consisting of alkyl, hydroxy alkyl and aralkyl groups, R2 is selected from the class consisting of the hydrogen atom and alkyl and aralkyl groups, A is an acid residue and n is selected from the class consisting of nought and l, with a quaternary salt of a heterocyclic nitrogen compound of the type used in cyanine dyes containing a reactive methylene group in one of the a and 1/ positions to the quaternary heterocyclic nitrogen atom.

5. Process for the production of dyestuffs which comprises condensing by heating together a dyestuff intermediate of the general formula:

where D is the residue of a heterocyclic nitrogen nucleus of the type used in cyanine dyes, R1 is selected from the class consisting of alkyl, hydroxy alkyl and aralkyl groups, A is an acid residue and n is selected from the class consisting of nought and l, with an alkyl quaternary salt of a heterocyclic nitrogen compound of the type used in cyanine dyes containing a lower alkyl group in one of the oz and 7 positions to the quaternary heterocyclic nitrogen atom,

6. Process for the production of dyestuffs which comprises condensing by heatin together a dyestuif intermediate of the eneral formula:

where D is the residue of a heterocyclic nitrogen nucleus of the type used in cyanine dyes, R1

is selected from the class consisting of alkyl, hydroxy alkyl and aralkyl groups, A is an acid residue and n is selected from the class consisting of nought and 1, with a heterocyclic nitrogen keto-methylene compound of the general 12 residue and n is selected from the class consisting of nought and 1, with a compound ofthe general formula:

where X is selected from the class consisting of oxygen and sulphur and R is selected from the class consisting of the hydrogen atom and hydro-- carbo n groups.

8. Process according to claim 7 wherein the product obtained is treated with a salt selected from the class consisting of alkyl and aralkyl salts and the quaternary salt thereby obtained is further reacted with a compound of the general formula:

whereX is selected from the classconsisting of oxygen and sulphur and R is selected from the class consisting of the hydrogen atom and hydrocarbon groups.

9. Process for the production of dyestuffs which comprises condensing by heating together a dyestuli intermediate of the general formula:

I I=(CH-CH)= (5( J=CHCH=C R; \A R,

where D is the residue of a heterocyclic nitrogen nucleus of the type used in cyanine dyes, R1 is selected from the class consisting of alkyl, hydroxy alkyl and aralkyl groups, R is selected from the class consisting of the hydrogen atom and alkyl' and aralkyl groups, R3 is a hydrocarbon group, R5 is selected from the class consisting'of alkyl and aralkyl groups, A is an acid residue, 12 is selected from the class consisting of nought and 1, with a quaternary salt of a heterocyclic nitrogen compound of the type used in cyanine dyes containing a reactive methylene group in one of the alpha and gamma positions to the quaternary heterocylic nitrogen atom.

10. Process for the production of dyestuffs which comprises condensing by heating together a dyestuff intermediate of the general formula':'

where D is the residue of a, heterocyclic ntrogen nucleus of the type used in cyanine dyes, R1 is selected from the class consisting of alkyl, hydroxyl alkyl and aralkyl groups, R2 is selected from the class consisting'of thehydrogen atom and alkyl and aralkyl groups, R3 is a hydrocarbon group, R5 is selected from the class consisting of alkyl and aralkyl groups, A is an acid residue, n is selected from the class consisting of nought and 1, with a compound containing a reactive methylene group taken from the class consisting of fivemembered heterocyclic nitrogen keto-methylene compounds, quaternary salts of heterocyclic ,nitrogen compounds having in one ofthe positions alpha and gamma to the heterocyclic nitrogen 13 atom a. reactive group taken from the class consisting of methyl and mono-substituted methyl groups.

JOHN DAVID KENDALL. HENRY WALTER WOOD. JOHN RAYMOND MAJER.

REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Name Date Brooker Feb. 23, 1932 Number Number Number Certificate of Correction Patent No. 2,527,259 October 24, 1950 JOHN DAVID KENDALL ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 27 for 011- read obtained as dark green crystals melting at 180 0.; line 30, strike out ver iodobromide emulsion imparts a band of;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 26th day of December, A. D. 1950.

. THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

1. PROCESS FOR THE PRODUCTION OF DYESTUFFS WHICH COMPRISES CONDENSING BY HEATING TOGETHER A DYESTUFF INTERMEDIATE OF THE GENERAL FORMULA: 